S. D. Pekarek, M. T. Lemanski, E. A. Walters, PC Krause and Associates, Inc; D. Delisle, Naval Surface Warfare Center Proceedings Naval Symposium on Electric Machines, October 1998, pp. 51-58.
Read MoreAn Accurate Method of Neglecting Dynamic Saliency of Synchronous Machines in Power Electronic Based Systems
S. D. Pekarek , E. A. Walters, PC Krause and Associates, Inc. IEEE Transactions on Energy Conversion, vol. 4, December 1999, pp.1177-1183.
Read MoreOn the Use of Singular Perturbations to Neglect the Dynamic Saliency of Synchronous Machines
S. D. Pekarek, M. Lemanski, Purdue University; E. A. Walters, PC Krause and Associates Inc. A common approximation used in the analysis of power systems is the neglect of the dynamic saliency in synchronous machines. In this paper, it is shown that eliminating the error associated with neglecting dynamic saliency can be accomplished with the addition of a singular perturbation(s) into the machine model. By considering the elimination of error in such a way, singular-perturbation-based model-order-reduction techniques are used to derive detailed- and reduced-order models of synchronous machines where dynamic saliency is eliminated with zero error and no added numerical cost. IEEE Transactions on Energy Conversion, vol. 17, issue 3, September 2002, pp....
Read MoreIntegrated Hardware-in-the-Loop Simulation of a Complex Turbine Engine and Power System
Suraj Ramalingam, Aaron Green, Peter Lamm, U.S. Air Force Research Laboratory; Hank Barnard, Scientific Monitoring, Inc; E. A. Walters, J. R. Wells, PC Krause and Associates, Inc. The interdependency between propulsion, power, and thermal subsystems on military aircraft such as the F-35 Joint Strike Fighter (JSF) and F-22 Raptor continues to increase as advanced war-fighting capabilities including solid-state radars, electronic attack, electric actuation, and Directed Energy Weaponry (DEW) expand to meet Air Force needs. Novel analysis and testing methodologies are required to predict these interdependencies and address adverse interactions prior to costly hardware prototyping. As a result, the Air Force Research Laboratory (AFRL) has established a dynamic hardware-in-the-loop (HIL) test-bed wherein transient simulations can be integrated through advanced real-time simulation with prototype hardware for integrated system studies and analysis. This paper details a test-bed configuration where a dynamic simulation of an aircraft turbine engine is utilized to control a dual-head electric drive stand. The drive stand is connected to an electric generator and associated power system implemented in hardware. The electromagnetic torque produced by the generator is measured and fed back into the turbine engine simulation as a load to the shaft. The HIL capability of this test-bed configuration enables reduced cost altitude testing, supports the design and analysis of integrated starter / generators and alternative power / propulsion architectures, and sets the stage for advanced integrated turbine engine / generator control design. 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
Read MoreCoupled-Circuit Modeling of 3, 6, and 9-Phase Induction Machine Drive Systems
Juri Jatskevich, University of British Columbia, Canada; E. A. Walters, C. E. Lucas, PC Krause and Associates, Inc. This paper describes a coupled-circuit physical-variable modeling of multiphase induction motors. The presented modeling interface makes it straightforward to implement an induction machine with arbitrary number of phases and/or phase groups on the stator and the rotor. The 3-, 6-, and 9-phase motors are simulated and compared. It is shown that machines with higher number of phases have less severe torque pulsation and the stator current increase following a loss of one phase. For the 9-phase machine, several studies involving loss of multiple phases are also presented, wherein the relative location of the faulted phases is shown to have a significant impact on redistribution of currents and resulting electromagnetic torque. The proposed models can be used to represent induction motors and generators for transient studies involving multiple faults, system-level reconfiguration, and survivability. 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
Read MoreTransient Turbine Engine Modeling and Real-Time System Integration Prototyping
Michael Corbett, Jessica Williams, Mitch Wolff, E. A. Walters, J. R. Wells, PC Krause and Associates, Inc; Peter Lamm, U.S. Air Force Research Laboratory Aircraft power demands continue to increase with the increase in electrical subsystems. These subsystems directly affect the behavior of the power and propulsion systems and can no longer be neglected or assumed linear in system analyses. The complex models designed to integrate new capabilities have a high computational cost. This paper investigates the possibility of using a hardware-in-the-loop (HIL) analysis with real time integration. A representative electrical power system is removed from a turbine engine model simulation and replaced with the appropriate hardware attached to a 350 horsepower drive stand. In order to update the model to proper operating conditions, variables are passed between the hardware and the computer model. Using this method, a significant reduction in runtime is seen, and the turbine engine model is usable in a real time environment. Scaling is also investigated for simulations to be performed that exceed the operating parameters of the drive stand. Similar results are generated with and without the scale factor implemented. Excellent agreement is shown between the HIL and stand alone model results. These results validate the capability of HIL experimentation and provide the opportunity for significant future propulsion configuration studies with minimal cost. 2006 SAE Power Systems Conference, November 7–9, 2006, New Orleans, LA. Paper...
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